Fix crash for Windows+Intel video card configuration

Intel video cards don't work fine with multiple contexts and
have to share the same context for all windows. This could work
incorrect with multiple video cards configuration, so suppose
there'll be no such situation (Intel cards are mostly in portable
devices like notebooks and laptops, where there's actually no
dual video cards). Anyway, it should work much better now.

Non-Intel cards behavior was kept unchanged.

Thanks to Ton for debug session :)

1 files changed, 43 insertions, 13 deletions

diff --git a/intern/ghost/intern/GHOST_WindowWin32.cpp b/intern/ghost/intern/GHOST_WindowWin32.cpp
index 0a660161cde..9b98cb8c0ac 100644
--- a/intern/ghost/intern/GHOST_WindowWin32.cpp
+++ b/intern/ghost/intern/GHOST_WindowWin32.cpp
@@ -105,6 +105,22 @@ static PIXELFORMATDESCRIPTOR sPreferredFormat = {
 	0, 0, 0                         /* no layer, visible, damage masks */
 };
 
+/* Intel videocards don't work fine with multiple contexts and
+   have to share the same context for all windows.
+   But if we just share context for all windows it could work incorrect
+   with multiple videocards configuration. Suppose, that Intel videocards
+   can't be in multiple-devices configuration. */
+static int is_crappy_intel_card(void)
+{
+	int crappy = 0;
+	const char *vendor = (const char*)glGetString(GL_VENDOR);
+
+	if (strstr(vendor, "Intel"))
+		crappy = 1;
+
+	return crappy;
+}
+
 GHOST_WindowWin32::GHOST_WindowWin32(
 	GHOST_SystemWin32 * system,
 	const STR_String& title,
@@ -707,15 +723,22 @@ GHOST_TSuccess GHOST_WindowWin32::installDrawingContext(GHOST_TDrawingContextTyp
 			}
 
 			// Create the context
-			m_hGlRc = ::wglCreateContext(m_hDC);
-			if (m_hGlRc) {
-				if (s_firsthGLRc) {
-					::wglCopyContext(s_firsthGLRc, m_hGlRc, GL_ALL_ATTRIB_BITS);
-					wglShareLists(s_firsthGLRc, m_hGlRc);
-				} else {
-					s_firsthGLRc = m_hGlRc;
+			if (s_firsthGLRc && is_crappy_intel_card()) {
+				m_hGlRc = s_firsthGLRc;
+			} else {
+				m_hGlRc = ::wglCreateContext(m_hDC);
+
+				if (m_hGlRc) {
+					if (s_firsthGLRc) {
+						::wglCopyContext(s_firsthGLRc, m_hGlRc, GL_ALL_ATTRIB_BITS);
+						::wglShareLists(s_firsthGLRc, m_hGlRc);
+					} else {
+						s_firsthGLRc = m_hGlRc;
+					}
 				}
+			}
 
+			if (m_hGlRc) {
 				success = ::wglMakeCurrent(m_hDC, m_hGlRc) == TRUE ? GHOST_kSuccess : GHOST_kFailure;
 			}
 			else {
@@ -743,14 +766,21 @@ GHOST_TSuccess GHOST_WindowWin32::installDrawingContext(GHOST_TDrawingContextTyp
 			::DescribePixelFormat(m_hDC, iPixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &preferredFormat);
 
 			// Create the context
-			m_hGlRc = ::wglCreateContext(m_hDC);
-			if (m_hGlRc) {
-				if (s_firsthGLRc) {
-					::wglShareLists(s_firsthGLRc, m_hGlRc);
-				} else {
-					s_firsthGLRc = m_hGlRc;
+			if (s_firsthGLRc && is_crappy_intel_card()) {
+				m_hGlRc = s_firsthGLRc;
+			} else {
+				m_hGlRc = ::wglCreateContext(m_hDC);
+
+				if (m_hGlRc) {
+					if (s_firsthGLRc) {
+						::wglShareLists(s_firsthGLRc, m_hGlRc);
+					} else {
+						s_firsthGLRc = m_hGlRc;
+					}
 				}
+			}
 
+			if (m_hGlRc) {
 				success = ::wglMakeCurrent(m_hDC, m_hGlRc) == TRUE ? GHOST_kSuccess : GHOST_kFailure;
 			}
 			else {